People are going to think I am off my rocker but my choice would be my S&W Model 57 Mountain Gun. Yes I know the .41 Mag is not all that popular but it is my favorite revolver round and if I could only have one it would be this one. A close second would be my S&W Model 64. It is the stainless version of the model 10. 4 in heavy barrel .38 Special K-Frame.